Solid catalyst components for olefin polymerization, catalysts for olefin polymerization and process for producing olefin polymers

ABSTRACT

Solid catalyst components for the polymerization of olefins, comprising titanium, magnesium and a compound of general formula (I), wherein R 1  and R 2  may be the same or different and each represents a linear or branched hydrocarbon group having 1 to 20 carbon atoms, and n is an integer of 1 to 10, as an electron donor, which are combined with organoaluminum compounds to form polymerization catalysts for the production of olefin polymers. This electron donor has no problems of safety and hygiene, and is inexpensive and easily synthesized. This compound can provide highly active and highly stereoregular solid catalyst components for the polymerization of olefins, catalysts for the polymerization of olefins, and processes for producing olefin polymers.

TECHNICAL FIELD

The present invention relates to solid catalyst components for olefinpolymerization and catalysts for olefin polymerization, which are forproducing homopolymers or copolymers of olefins throughhomopolymerization or copolymerization of ethylene and other α-olefins,and also to processes for producing olefin polymers.

BACKGROUND OF THE INVENTION

Many solid catalyst components have heretofore been proposed, whichcomprise, as the essential catalyst ingredients, magnesium, titanium,halogens and electron donors. It is well known that these catalystsdisplay high activity in olefin polymerization, and exhibit highstereospecificity in polymerization of α-olefins. In particular, it isknown that solid catalyst components comprising, as electron donors,aromatic esters such as typically phthalates have excellent catalyticcapabilities. However, using aromatic compounds is often dislikedbecause of their problems of safety and hygiene.

Using malonate derivatives as non-aromatic electron donors has beenproposed. For example, in Japanese Patent Publication No. 80044/1992,proposed are compounds of a general formula (II):

wherein either one or both of R³ and R⁴ are linear or branchedhydrocarbon groups each having 4 carbon atoms, or aromatic hydrocarbongroups. However, using the compounds does not provide satisfactorystereospecificity in polymer production. In Japanese Patent Laid-OpenNo. 122716/1994, proposed are compounds of formula (II) where R³ and R⁴are bonded to each other to form a cyclic structure. In Japanese PatentLaid-Open No. 279517/1994, proposed are compounds of formula (II) whereR³ and R⁴ are both hydrogen atoms; those where either one of R³ and R⁴is a linear or branched hydrocarbon group having at least one carbonatom, or an aromatic hydrocarbon group, and where the other is ahydrogen atom; and those where both R³ and R⁴ are linear hydrocarbongroups each having at least 2 carbon atoms. However, using the compoundsprovides extremely poor yields of polymers. In Japanese Patent Laid-OpenNo. 157521/1996, proposed are compounds of formula (II) where both R³and R⁴ are branched or cyclic hydrocarbon groups each having at least 3carbon atoms. However, the malonates having such branched or cyclichydrocarbon groups are difficult to produce, and, in addition, usingthem provides poor yields of polymers and is therefore impracticable. InJapanese Patent Laid-Open Nos. 124705/1991 and 168207/1991, using othernon-aromatic diesters as electron donors is proposed. However, thenon-aromatic diesters proposed are not always satisfactory for providinga high yields of stereospecific polymers.

The object of the present invention is to provide solid catalystcomponents for olefin polymerization, catalysts for olefinpolymerization and processes for producing olefin polymers, for whichare used, as electron donors, compounds having no problems of safety andhygiene. The compounds for electron donors are inexpensive and are easyto produce, and display high activity and high stereospecificity inolefin polymerization.

DISCLOSURE OF THE INVENTION

We, the present inventors have assiduously studied so as to attain theobject as above, and, as a result, have found that using solid catalystcomponents for olefin polymerization, which comprise titanium,magnesium, and a compound of the following general formula (I) as anelectron donor solves the problems noted above. On the basis of thisfinding, we have completed the present invention.

Specifically, the invention provides solid catalyst components forolefin polymerization, catalysts for olefin polymerization, andprocesses for producing olefin polymers, which are as follows:

(1) A solid catalyst component for olefin polymerization, comprisingtitanium, magnesium, and a compound of the following general formula (I)as an electron donor:

wherein R¹ and R²may be the same or different and each represents alinear or branched hydrocarbon group having from 1 to 20 carbon atoms;and n is an integer of from 1 to 10.

(2) A catalyst for olefin polymerization, comprising (A) the solidcatalyst component for olefin polymerization of (1), and (B) anorganoaluminium compound.

(3) A catalyst for olefin polymerization, comprising (A) the solidcatalyst component for olefin polymerization of (1), (B) anorganoaluminium compound, and (C) an electron-donating compound as thethird component.

(4) The catalyst for olefin polymerization of (3), wherein theelectron-donating compound for the third component (C) is anorganosilicon compound.

(5) A process for producing olefin polymers, which comprisespolymerizing olefins in the presence of the catalyst for olefinpolymerization of any one of (2) to (4).

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a flowchart showing one embodiment of olefin polymerization ofthe invention.

BEST MODES OF CARRYING OUT THE INVENTION

The solid catalyst component for olefin polymerization of the inventionis characterized by comprising titanium, magnesium, and a compound ofthe following general formula (I) as an electron donor:

wherein R¹ and R²maybe the same or different and each represents alinear or branched hydrocarbon group having from 1 to 20 carbon atoms;and n is an integer of from 1 to 10.

The catalyst for olefin polymerization of the invention is characterizedby comprising (A) the solid catalyst component for olefin polymerizationas above, (B) an organoaluminium compound, and optionally (C) anelectron-donating compound as the third component.

The process for producing olefin polymers of the invention ischaracterized by polymerizing olefins in the presence of the catalystfor olefin polymerization as above.

The catalyst components, methods for preparing them, and polymerizationprocesses are described below.

[I] Catalyst Components

(A) Solid Catalyst Components for Olefin Polymerization:

The solid catalyst component for olefin polymerization comprisestitanium, magnesium, and an electron donor, and is made from thefollowing titanium compound (a), magnesium compound (b) and electrondonor (c).

(a) Titanium Compound:

Titanium compounds of the following general formula (III) may be used inthe invention:

TiX¹ _(p)(OR⁵)_(4−p)  (III)

In formula (III), X¹ represents a halogen atom, and is preferably achlorine or bromine atom. More preferred is a chlorine atom. R⁵represents a hydrocarbon group, which may be saturated or unsaturated,and may be linear, branched or cyclic. It may contain hetero atoms ofsulfur, nitrogen, oxygen, silicon, phosphorus, etc., but is preferably ahydrocarbon group having from 1 to 10 carbon atoms, more preferably analkyl, alkenyl, cycloalkenyl, aryl or aralkyl group, even morepreferably a linear or branched alkyl group. Plural —OR⁵'s, if any, maybe all the same or be of different compositions. Specific examples of R⁵include a methyl group, an ethyl group, an n-propyl group, an isopropylgroup, an n-butyl group, a sec-butyl group, an isobutyl group, a pentylgroup, a hexyl group, a heptyl group, an octyl group, a decyl group, anallyl group, a butenyl group, a cyclopentyl group, a cyclohexyl group, acyclohexenyl group, a phenyl group, a tolyl group, a benzyl group, aphenethyl group, etc. p is an integer of from 0 to 4.

Specific examples of the titanium compounds of formula (III) includetetraalkoxytitaniums such as tetramethoxytitanium, tetraethoxytitanium,tetra-n-propoxytitanium, tetraisopropoxytitanium,tetra-n-butoxytitanium, tetraisobutoxytitanium,tetracyclohexyloxytitanium, tetraphenoxytitanium, etc.; titaniumtetrahalides such as titanium tetrachloride, titanium tetrabromide,titanium tetraiodide, etc.; alkoxytitanium trihalides such asmethoxytitanium trichloride, ethoxytitanium trichloride, propoxytitaniumtrichloride, n-butoxytitanium trichloride, ethoxytitanium tribromide,etc.; dialkoxytitanium dihalides such as dimethoxytitanium dichloride,diethoxytitanium dichloride, diisopropoxytitanium dichloride,di-n-propoxytitanium dichloride, diethoxytitanium dibromide, etc.;trialkoxytitanium monohalides such as trimethoxytitanium chloride,triethoxytitanium chloride, triisopropoxytitanium chloride,tri-n-propoxytitanium chloride, tri-n-butoxytitanium chloride, etc. Ofthose, preferred are high-halogen titanium compounds, and especiallypreferred is titanium tetrachloride. One or more of these titaniumcompounds may be used either singly or as combined.

(b) Magnesium Compound:

Magnesium compounds of the following formula (IV) may be used in theinvention.

 MgR⁶R⁷  (IV)

In formula (IV), R⁶ and R⁷ each represent a hydrocarbon group, an OR⁸group (where R8 indicates a hydrocarbon group), or a halogen atom. Moreprecisely, the hydrocarbon group may be an alkyl, cycloalkyl, aryl oraralkyl group having from 1 to 12 carbon atoms. In OR⁸, R⁸ represents analkyl, cycloalkyl, aryl or aralkyl group having from 1 to 12 carbonatoms. The halogen atom includes chlorine, bromine, iodine and fluorineatoms. R⁶ and R⁷ may be the same or different.

Specific examples of the magnesium compounds of formula (IV) includealkylmagnesiums and arylmagnesiums such as dimethylmagnesium,diethylmagnesium, diisopropylmagnesium, dibutylmagnesium,dihexylmagnesium, dioctylmagnesium, ethylbutylmagnesium,diphenylmagnesium, dicyclohexylmagnesium, etc.; alkoxymagnesiums andaryloxymagnesiums such as dimethoxymagnesium, diethoxymagnesium,dipropoxymagnesium, dibutoxymagnesium, dihexyloxymagnesium,dioctoxymagnesium, diphenoxymagnesium, dicyclohexyloxymagnesium, etc.;alkylmagnesium halides and arylmagnesium halides such as ethylmagnesiumchloride, butylmagnesium chloride, hexylmagnesium chloride,isopropylmagnexium chloride, isobutylmagnesium chloride,t-butylmagnesium chloride, phenylmagnesium bromide, benzylmagnesiumchloride, ethylmagnesium bromide, butylmagnesium bromide,phenylmagnesium chloride, butylmagnesium iodide, etc.; alkoxymagnesiumhalides and aryloxymagnesium halides such as butoxymagnesium chloride,cyclohexyloxymagnesium chloride, phenoxymagnesium chloride,ethoxymagnesium bromide, butoxymagnesium bromide, ethoxymagnesiumiodide, etc.; magnesium halides such as magnesium chloride, magnesiumbromide, magnesium iodide, etc.

Of those magnesium compounds, preferred are magnesium halides,alkoxymagnesiums, alkylmagnesiums, and alkylmagnesium halides.

As the magnesium compounds, also usable herein are reaction products ofmetal magnesium with an alcohol, and a halogen and/or ahalogen-containing compound. Catalysts comprising such magnesiumreaction products are preferred, as having higher catalyst activity,capable of displaying better stereospecificity, and capable of carryinga larger amount of titanium therewith. In the presence of suchcatalysts, therefore, obtainable are powdery polymers having bettermorphology. The shape of the metal magnesium to be used in preparing themagnesium reaction products is not specifically defined, and metalmagnesium of any shape is employable. For example, the metal magnesiummay be any of granular, ribbon-like or powdery magnesium. The surfacecondition of the metal magnesium is not also specifically defined.Preferably, however, the metal magnesium for use herein is not coatedwith a film of magnesium oxide or the like.

The alcohol for use herein is not also specifically defined. Preferredis a lower alcohol having from 1 to 6 carbon atoms, and especiallypreferred is ethanol, as providing solid catalysts having bettercatalytic capabilities. The purity and the water content of the alcoholare not also specifically defined. However, alcohols with much waterwill form magnesium hydroxide on the surface of metal magnesium.Therefore, it is desirable to use alcohols having a water content of atmost 1% by weight, more preferably at most 2000 ppm. For preparingmagnesium compounds capable of providing polymers with bettermorphology, preferred are alcohols having a smaller water content.

The type of the halogen for use herein is not also specifically defined.Preferred is chlorine, bromine or iodine, and especially preferred isiodine. The halogen-containing compound is not also specificallydefined, and it may be any compound containing a halogen atom in itsmolecule. The type of the halogen atom to be in the compound is notspecifically defined, but preferred are chlorine, bromine and iodine. Asthe halogen-containing compound, preferred are halogen-containing metalcompounds.

Specific examples of the halogen-containing compounds include MgCl₂,MgI₂, Mg(OEt)Cl, Mg(OEt)I, MgBr₂, CaCl₂, NaCl, KBr, etc. Especiallypreferred are MgCl₂ and MgI₂. The condition, the shape and the grainsize of those compounds are not specifically defined. For example, thecompounds may be used in the form of their solutions in alcohols such asethanol, etc.

The a mount of the alcohol to be used in the reaction may fall generallybetween 2 and 100 mols, preferably between 5 and 50 mols, relative toone mol of metal magnesium. If the amount of the alcohol is too large,magnesium compounds capable of providing polymers with good morphologyare difficult to prepare; but if too small, the reaction with metalmagnesium will not progress well. The amount of the halogen or thehalogen-containing compound to be used in the reaction may be generallyat least 0.0001 gram atoms, preferably at least 0.0005 gram atoms, morepreferably at least 0.001 gram atoms, even more preferably at least 0.01gram atoms, in terms of the halogen element relative to 1 mol of metalmagnesium. If the amount of the halogen is smaller than 0.0001 gramatoms and if the magnesium compounds prepared are used without beingground, the amount of titanium to be carried on the compounds will below. If so, in addition, the catalytic activity of the compounds will below, and the stereospecificity and the morphology of the polymers to beproduced will be not good. Therefore, grinding the magnesium compoundsprepared is indispensable. For these reasons, using such a small amountof the halogen is unfavorable. The uppermost limit of the halogen to beused is not specifically defined, and may be suitably determined withinthe range within which the desired amount of magnesium compounds will beprepared. Using suitable amount of halogen, the grain size of themagnesium compounds to be prepared can be controlled to any desiredrange.

The reaction of metal magnesium with an alcohol, and a halogen orhalogen-containing compound may be effected in any desired manner. Forexample, metal magnesium may be reacted with an alcohol, and a halogenor halogen-containing compound under reflux, until no hydrogen gas isformed any more in the reaction system, generally requiring from 20 to30 hours. The desired magnesium compounds are thus produced. Concretely,where iodine is used as the halogen, solid iodine is put into a mixtureof metal magnesium and an alcohol, and heated under reflux; or analcohol solution containing iodine is dropwise added to a mixture ofmetal magnesium and an alcohol, and heated under reflux; or while amixture of metal magnesium and an alcohol is heated, an alcohol solutioncontaining iodine is dropwise added to the mixture. In any of thesemethods, the reaction is preferably effected in an inert gas atmosphereof, for example, nitrogen gas, argon gas or the like, in the presence ofan inert organic solvent of, for example, a saturated hydrocarbon suchas hexane or the like. Regarding the mode of putting metal magnesium andthe alcohol into the reactor, it is not always necessary to put all ofthem into the reactor from the start of the reaction, but they may bedivided into plural portions and the portions may be separately andintermittently fed into the reactor. One preferred mode is such that theentire amount of the alcohol to be reacted is first put into the reactorprior to the start of the reaction, and metal magnesium having beendivided into plural portions is intermittently fed into the reactor.According to the method of this mode, a large quantity of hydrogen gasis prevented from being formed all at a time. Therefore, the method ispreferred in view of the safety in the reaction. In addition, thereactor for the method can be small-sized. What is more, since a largequantity of hydrogen gas is not formed all at a time in the method, theunreacted magnesium and halogen are prevented from being scattered tocontaminate the magnesium compounds produced. The number of the portionsof the reactants to be divided for the reaction is not specificallydefined. It could be determined, depending on the size or the scale ofthe reactor to be used. For easy operation, in general, it is usuallydivided into between 5 and 10.

The reaction may be either a batchwise or continuous one. If desired, asmall amount of metal magnesium is added to a reactor, into which theentire amount of an alcohol has been previously put prior to the startof the reaction, and the product produced through the reaction of thetwo is taken out. Then, another small amount of metal magnesium is addedthereto, and the cycle of magnesium addition and product collection maybe repeated.

The reaction product thus prepared is filtered and then dried. In thatmanner, obtained are the desired magnesium compounds. The magnesiumcompounds may be used in the next step, without being purified, groundor classified. The magnesium compounds contain a halogen, in addition tothe magnesium component and the alcohol component.

One or more of the magnesium compounds as above may be used eithersingly or as combined.

(c) Electron Donor:

As the electron donor, usable are compounds of the following generalformula (I):

wherein R¹ and R² may be the same or different and each represents alinear or branched hydrocarbon group having from 1 to 20 carbon atoms;and n is an integer of from 1 to 10.

Specific examples of R¹ and R² include methyl, ethyl, n-propyl,i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, n-hexyl,n-octyl and 2-ethylhexyl groups, etc. Preferred are hydrocarbon groupseach having from 3 to 8 carbon atoms; and more preferred are n-butyl andi-butyl groups.

Specific examples of the compounds include dimethyl dimethylmalonate,diethyl dimethylmalonate, di-n-propyl dimethylmalonate, di-i-propyldimethylmalonate, di-n-butyl dimethylmalonate, di-i-butyldimethylmalonate, di-t-butyl dimethylmalonate, di-n-pentyldimethylmalonate, di-i-pentyl dimethylmalonate, neopentyldimethylmalonate, di-n-hexyl dimethylmalonate, di-n-heptyldimethylmalonate, di-n-octyl dimethylmalonate, di(2-ethylhexyl)dimethylmalonate, etc. Of those, especially preferred is di-n-butyldimethylmalonate. One or more of these compounds may be used eithersingly or combined.

(d) Silicon Compound:

In preparing the solid catalyst components, if desired, a siliconcompound of the following general formula (V) may be used as thecomponent (d), in addition to the above components (a), (b) and (c).

Si(OR⁹)_(q)X² _(4−q)  (V)

In formula (V), X² represents a halogen atom, and is preferably achlorine or bromine atom, more preferably a chlorine atom. R⁹ representsa hydrocarbon group, which may be saturated or unsaturated, and may belinear, branched or cyclic. It may contain hetero atoms of sulfur,nitrogen, oxygen, silicon, phosphorus, etc., but is preferably ahydrocarbon group having from 1 to 10 carbon atoms, more preferably analkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl or aralkyl group. PluralR⁹'s, if any, may be all the same or have different compositions.Specific examples of R⁹ include a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group,an isobutyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a decyl group, an allyl group, a butenyl group, acyclopentyl group, a cyclohexyl group, a cyclohexenyl group, a phenylgroup, a tolyl group, a benzyl group, a phenethyl group, etc. q is aninteger of from 0 to 3.

Specific examples of the silicon compounds of formula (V) include SiCl₄,CH₃OSiCl₃, (CH₃O)₂SiCl₂, (CH₃O)₃SiCl, C₂H₅OSiCl₃, (C₂H₅O)₂SiCl₂,(C₂H₅O)₃SiCl, C₃H₇OSiCl₃, (C₃H₇O)₂SiCl₂, (C₃H₇O)₃SiCl, etc. Of those,especially preferred is silicon tetrachloride, One of more of thesesilicon compounds may be used either singly or combined.

Regarding the amount of the silicon compound to be used herein as theoptional component (d), the ratio by mol of silicon compound/magnesiumcompound should be generally at least 0.01, preferably at least 0.10. Ifthe molar ratio is smaller than 0.01, the silicon compound used will notsatisfactorily display its potential to improve the activity and thestereospecificity of the catalyst, and in addition, the proportion offine powder among the polymers produced in the presence of the catalystwill increase.

(B) Organoaluminium Compounds:

Organoaluminium compounds (B) to be used in the invention may be thosecontaining any of alkyl groups, halogen atoms, hydrogen atoms, andalkoxy groups, as well as aluminoxanes and their mixtures. Concretely,they include trialkylaluminiums such as trimethylaluminium,triethylaluminium, triisopropylaluminium, triisobutylaluminium,trioctylaluminium, etc.; dialkylaluminium monochlorides such asdiethylaluminium monochloride, diisopropylaluminium monochloride,diisobutylaluminium monochloride, dioctylaluminium monochloride, etc.;alkylaluminium sesqui-halides such as ethylaluminium sesqui-chloride,etc.; linear aluminoxanes such as methylaluminoxane, etc. Of thoseorganoaluminium compounds, preferred are trialkylaluminiums with loweralkyl groups each having from 1 to 5 carbon atoms; and especiallypreferred are trimethylaluminium, triethylaluminium, tripropylaluminium,and triisobutylaluminium. One or more of these organoaluminium compoundsmay be used either singly or combined.

(C) Third Component (electron-donating compounds):

The catalyst for olefin polymerization of the invention optionallycontains an electron-donating compound as the component (C). Theelectron-donating compound for the component (C) includes alkoxygroup-having organosilicon compounds, nitrogen-containing compounds,phosphorus-containing compounds, and oxygen-containing compounds. Ofthose, preferred are alkoxy group-having organosilicon compounds.

Specific examples of the alkoxy group-having organosilicon compoundsinclude tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane,tetraisobutoxysilane, trimethylmethoxysilane, trimethylethoxysilane,triethylmethoxysilane, triethylethoxysilane,ethylisopropyldimethoxysilane, propylisopropyldimethoxysilane,diisopropyldimethoxysilane, diisobutyldimethoxysilane,isopropylisobutyldimethoxysilane, di-t-butyldimethoxysilane,t-butylmethyldimethoxysilane, t-butylethyldimethoxysilane,t-butylpropyldimethoxysilane, t-butylisopropyldimethoxysilane,t-butylbutyldimethoxysilane, t-butylisobutyldimethoxysilane,t-butyl(s-butyl)dimethoxysilane, t-butylamyldimethoxysilane,t-butylhexyldimethoxysialne, t-butylheptyldimethoxysilane,t-butyloctyldimethoxysilane, t-butylnonyldimethoxysilane,t-butyldecyldimethoxysilane,t-butyl(3,3,3-trifluoromethylpropyl)dimethoxysilane,cyclopentyl-t-butyldimethoxysilane, cyclohexyl-t-butyldimethoxysilane,dicyclopentyldimethoxysilane, bis(2-methylcyclopentyl)dimethoxysilane,bis(2,3-dimethylcyclopentyl)dimethoxysilane, diphenyldimethoxysilane,phenyltriethoxysilane, methyltriethoxysilane, ethyltriethoxysilane,propyltrimethoxysilane, isopropyltrimethoxysilane,butyltrimethoxysilane, isobutyltrimethoxysilane,t-butyltrimethoxysilane, s-butyltrimethoxysilane, amyltrimethoxysilane,isoamyltrimethoxysilane, cyclopentyltrimethoxysilane,cyclohexyltrimethoxysilane, norbornanetrimethoxysilane,indenyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane,cyclopentyl(t-butoxy) dimethoxysilane, isopropyl (t-butoxy)dimethoxysilane, t-butyl(isobutoxy)dimethoxysilane,t-butyl(t-butoxy)dimethoxysilane, thexyltrimethoxysilane,thexylisopropoxydimethoxysilane, thexyl(t-butoxy)dimethoxysilane,thexylmethyldimethoxysilane, thexylethyldimethoxysilane,thexylisopropyldimethoxysilane, thexylcyclopentyldimethoxysilane,thexylmyristyldimethoxysilane, thexylcyclohexyldimethoxysilane,neopentylpentyldimethoxysilane, diisopentyldimethoxysilane,isopentylisobutyldimethoxysilane, neopentylisopentyldimethoxysilane,etc. One of more of these organosilicon compounds may be used eithersingly or combined.

Specific examples of the nitrogen-containing compounds include2,6-substituted piperidines such as 2,6-diisopropylpiperidine, 2,6-diisopropyl-4-methylpiperidine,N-methyl-2,2,6,6-tetramethylpiperidine, etc.; 2,5-substituted azolidinessuch as 2,5-diisopropylazolidine, N-methyl-2,2,5,5-tetramethylazolidine,etc.; substituted methylenediamines such asN,N,N′,N′-tetramethylmethylenediamine,N,N,N′,N′-tetraethylmethylenediamine, etc.; substituted imidazolidinessuch as 1,3-dibenzylimidazolzidine, 1,3-dibenzyl-2-phenylimidazolidine,etc.

Specific examples of the phosphorus-containing compounds includephosphites such as triethyl phosphite, tri-n-propyl phosphite,triisopropyl phosphite, tri-n-butyl phosphite, triisobutyl phosphite,diethyl-n-butyl phosphite, diethylphenyl phosphite, etc.

Specific examples of the oxygen-containing compounds include2,6-substituted tetrahydrofurans such as2,2,6,6-tetramethyltetrahydrofuran, 2,2,6,6-tetraethyltetrahydrofuran,etc.; dimethoxymethane derivatives such as1,1-dimethoxy-2,3,4,5-tetrachlorocyclopentadiene, 9,9-dimethoxyfluorene,diphenyldimethoxymethane, etc.

[II] Preparation of Solid Catalyst Components

To prepare the solid catalyst components (A) as above, the titaniumcompound (a), the magnesium compound (b), the electron donor (c) andoptionally the silicon compound (d) are brought into contact with eachother by ordinary methods.

For bringing them into contact with each other, employable are knownmethods such as those described in Japanese Patent Laid-Open Nos.43094/1978, 135102/1980, 135103/1980, 18606/1981, etc. For example,employable are (1) a method comprising grinding a magnesium compound, ora complex compound of a magnesium compound with a dimalonate compound,in the presence of a dimalonate compound and optionally a grindingpromoter, followed by reacting the thus-ground powder with a titaniumcompound; (2) a method comprising reacting a liquid magnesium compoundnot having reducing capabilities with a liquid titanium compound in thepresence of a dimalonate compound, thereby giving a precipitate of asolid titanium complex; (3) a method of further reacting the product in(1) or (2) with a titanium compound; (4) a method of further reactingthe product in (1) or (2) with a dimalonate compound and a titaniumcompound; and (5) a method comprising grinding a magnesium compound, ora complex compound of a magnesium compound with a dimalonate compound,in the presence of a dimalonate compound, a titanium compound andoptionally a grinding promoter, followed by processing the thus-groundpowder with a halogen or a halogen compound.

Apart from the methods as above, still further employable are themethods described in Japanese Patent Laid-Open Nos. 166205/1981,63309/1982, 190004/1982, 300407/1982, 47003/1983, etc., for preparingthe solid catalyst components (A).

What is more, still another method is employable for preparing the solidcatalyst components. The method comprises bringing into contact a solidoxide of an element of Groups II to IV of the Periodic Table (e.g.,silicon oxide, magnesium oxide, etc.), or a solid composite oxidecontaining at least one oxide of an element of Groups II to IV of thePeriodic Table (e.g., silica-alumina, etc.), which carries therewith amagnesium compound such as that noted above, with an electron donor anda titanium compound, in a solvent at a temperature falling between 0 and200° C., preferably between 10 and 150° C., for a period of from 2minutes to 24 hours.

It is desirable that the amount of the titanium compound to be used forthe reaction falls generally between 0.5 and 100 mols, but preferablybetween 1 and 50 mols, relative to one mol of magnesium in the magnesiumcompound to be reacted therewith. It is also desirable that the amountof the electron donor for the reaction falls generally between 0.01 and10 mols, but preferably between 0.05 and 1.0 mol, relative to one mol ofmagnesium in the magnesium compound to be reacted therewith. If desired,a halide such as silicon tetrachloride maybe added to the reactionsystem.

The temperature for the contact of the components may fall generallybetween −20 and 200° C., preferably between 20 and 150° C. The time forthe contact thereof may fall generally between 1 minute and 24 hours,preferably between 10 minutes and 6 hours.

The order for bringing into contact the components with each other isnot specifically defined. For example, the components may be broughtinto contact with each other in the presence of an inert solvent of, forexample, hydrocarbons and the like; or the components may be previouslydiluted with an inert solvent of, for example, hydrocarbons and thelike, and then brought into contact with each other. The inert solventincludes, for example, aliphatic hydrocarbons such as n-pentane,isopentane, n-hexane, n-heptane, n-octane, isooctane, etc.; aromatichydrocarbons such as benzene, toluene, xylene, etc.; and their mixtures.

If desired, brought the components into contact with a titanium compoundmay be repeated twice or more, whereby the magnesium compound serving asa catalyst carrier could well carry the titanium compound therewith.

The solid catalyst components thus prepared through the contactingoperation as above may be washed with an inert solvent of, for example,hydrocarbons and the like. The inert solvent may be the same as above.The solid products may be stored in dry, or in an inert solvent of, forexample, hydrocarbons and the like.

[III] Polymerization

Regarding the amount of the catalyst components of the invention forpolymerization, the solid catalyst component (A) may be used generallyin an amount of from 0.0005 to 1 mmol in terms of the titanium atomtherein, per one liter of the reaction capacity; and the amount of theorganoaluminium compound (B) may be so controlled that the atomic ratioof aluminium/titanium falls generally between 1 and 1000, preferablybetween 10 and 500. If the atomic ratio oversteps the defined range, thecatalyst activity will be low. The amount of the electron-donatingcompound of the component (C) may be so controlled that the molar ratioof electron-donating compound (C)/organoaluminium compound (B) fallsgenerally between 0.001 and 5.0, preferably between 0.01 and 2.0, morepreferably between 0.05 and 1.0. If the molar ratio oversteps thedefined range, the catalyst could not have good activity.

As olefins to be polymerized herein, preferred are α-olefins of ageneral formula (VI):

R¹⁰—CH═CH₂  (VI)

In formula (VI), R¹⁰ represents a hydrogen atom, or a hydrocarbon group.The hydrocarbon group may be saturated or unsaturated, and may belinear, branched or cyclic. Specific examples of such α-olefins includeethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-decene, 3-methyl-1-pentene, 4-methyl-1-pentene, vinylcyclohexane, etc.One or more of these olefins may be homopolymerized or copolymerized.

Of the olefins noted above, especially preferred are ethylene andpropylene. In addition, dienes such as butadiene, etc., and any othervarious olefins are also employable herein for polymerization.

Regarding their polymerization mode in the invention, optionally,olefins may be pre-polymerized and then polymerized. In that case, forexample, olefins are first pre-polymerized in the presence of a catalyst(the catalyst is prepared by mixing the solid catalyst component (A),the organoaluminium compound and (C) the electron-donating compound in apredetermined ratio), at a temperature generally falling between 1 and100° C. and under a pressure generally falling between normal pressureand 50 kg/cm²G or so, and then further polymerized in the presence ofthe catalyst and the prepolymer having been produced in thepre-polymerization step. The polymerization mode in the finalpolymerization step is not specifically defined. The finalpolymerization may be effected in any mode of solution polymerization,slurry polymerization, vapor-phase polymerization, bulk polymerizationand so on, to which is applicable any of batch polymerization orcontinuous polymerization, or even two-stage or higher poly-stagepolymerization in which different stages are effected in differentconditions.

Regarding the reaction condition, the polymerization pressure is notspecifically defined, and may fall generally between atmosphericpressure and 80 kg/cm²G, preferably between 2 and 50 kg/cm²G, thepolymerization temperature may fall generally between 0 and 200° C.,preferably between 30 and 100° C. As depending on the type of thestarting material, olefins and on the polymerization temperature, thepolymerization time could not be determined indiscriminately, but mayfall generally between 5 minutes and 20 hours or so, preferably between10 minutes and 10 hours or so.

The molecular weight of the polymers to be produced could be controlledby adding a chain transfer agent, preferably hydrogen to thepolymerization system. If desired, the polymerization may be effected inthe presence of an inert gas such as nitrogen or the like.

Regarding the catalyst components of the invention to be used in thepolymerization, the components (A), (B) and (C) may be premixed in apredetermined ratio and directly contacted with each other, to whicholefins may be immediately applied and polymerized in the presence ofthe thus-prepared catalyst. Alternatively, after the components havebeen contacted with each other, the resulting catalyst may be ripenedfor 0.2 to 3 hours or so, and thereafter olefins may be applied andpolymerized in the presence of the thus-ripened catalyst. If desired,the catalyst components may be previously suspended in an inert solventor an olefin, and then fed into the polymerization system.

In the invention, the post-treatment after polymerization may beeffected in any ordinary manner. For example, in vapor-phasepolymerization, the powdery polymer produced is taken out of thepolymerization reactor, and then passed through a nitrogen streamatmosphere so as to remove the non-reacted olefins from it. If desired,the polymer may be pelletized through an extruder. In this step, a smallamount of water, an alcohol or the like may be added to the polymer soas to completely inactivate the catalyst. In bulk polymerization, thepolymer produced is taken out of the polymerization reactor, thenmonomers are completely removed from it, and thereafter the polymer maybe pelletized.

EXAMPLES

The invention is concretely described hereinunder with reference to thefollowing Examples, which, however, are not intended to restrict thescope of the invention. The intrinsic viscosity [η] and thestereospecificity [mmmm] of the polymers produced were obtainedaccording to the methods mentioned below.

Intrinsic Viscosity [η]:

A sample was dissolved in decalin, and its intrinsic viscosity wasmeasured at 135° C.

Stereospecificity [mmmm]:

A polymer sample was dissolved in a mixed solvent of1,2,4-trichlorobenzene and heavy benzene (90/10, by volume), andsubjected to a proton complete decoupling method for ¹³C-NMR (usingJEOL' LA-500) at 130° C. Based on the signals for the methyl groupobtained in the method, the stereospecificity [mmmm] of the sample wasdetermined. The stereospecificity was proposed by A. Zambelli et al. in“Macromolecules, 6, 925 (1973)”, and it indicates the isotactic fractionin the pentad unit of a polypropylene molecular chain as measured in ¹³Cnuclear magnetic resonance spectrometry. For the attribution of thepeaks seen in the ¹³C nuclear magnetic resonance spectrometry, referredto was the A. Zambelli et al's proposal in “Macromolecules, 8, 687(1975)”.

Example 1 (1) Preparation of Solid Catalyst Component

A three-neck flask having a capacity of 0.5 liters and equipped with astirrer was purged with nitrogen gas, into which were put 60 ml ofdewatered heptane and 4.0 g (35 mmols) of diethoxymagnesium. After themixture in the flask was heated at 40° C. for 20 minutes, 2.2 ml (9mmols) of di-n-butyl dimethylmalonate was added thereto. Then, theresulting solution was heated up to 90° C., and 116 ml (1.04 mols) oftitanium tetrachloride was added thereto. The mixture was stirred for 2hours at an inner temperature of 110° C. Through the treatment, thecarrier component carried the catalytic component therewith. Next, thethus-carried catalytic component was fully washed with dewateredheptane. 116 ml (1.04 mols) of titanium tetrachloride was again addedthereto, and stirred for 2 hours at an inner temperature of 110° C. Thisis for the second treatment for making the carrier component carry thecatalytic component therewith. After the second treatment, thethus-carried catalytic component was again fully washed with dewateredheptane. Thus was prepared a solid catalyst component (amount oftitanium carried=1.21% by weight).

(2) Slurry Polymerization of Propylene

A stainless steel autoclave having a capacity of 1 liter and equippedwith a stirrer was fully dried, and then purged with nitrogen. 400 ml ofdewatered heptane was put into the autoclave at room temperature. Next,0.5 mmols of triethylaluminium, 0.25 mmols ofdicyclopentyldimethoxysilane, and 0.005 mmols, in terms of the Ti atomtherein, of the solid catalyst component prepared above were put intothe autoclave, into which hydrogen was fed under 1 kg/cm²G.Subsequently, propylene was introduced into the autoclave, while beingheated at 80° C. to have a total pressure of 8 kg/cm²G. In thatcondition, propylene was polymerized for 60 minutes. After this, thereaction system was cooled and degassed, and the product was taken outof the autoclave, put into 2 liters of methanol in which the catalystwas inactivated. The thus-processed product was filtered, and theresulting residue was dried in vacuum. Thus was obtained a propylenepolymer (catalyst activity: 436 kg-PP/g-Ti). The viscosity [η] of thepolymer was 1.12 dl/g, and the stereospecificity [mmmm] thereof was97.3%.

Example 2

In the same manner as in [Example 1], a catalyst was prepared and amonomer propylene was polymerized in the presence of the catalyst. Inthis, however, di-n-heptyl dimethylmalonate was used in place ofdi-n-butyl dimethylmalonate in preparing the solid catalyst component.The amount of Ti carried in the solid catalyst component was 1.8% byweight. The polymerization activity of the catalyst was 336 kg-PP/g-Ti;[η] of the polymer was 1.10 dl/g; and the stereospecificity [mmmm] ofthe polymer was 96.7%.

Comparative Example 1

In the same manner as in [Example 1], a catalyst was prepared and amonomer propylene was polymerized in the presence of the catalyst. Inthis, however, diethyl diisobutylmalonate was used in place ofdi-n-butyl dimethylmalonate in preparing the solid catalyst component.The amount of Ti carried in the solid catalyst component was 2.8% byweight. The polymerization activity of the catalyst was 297 kg-PP/g-Ti;[η] of the polymer was 1.09 dl/g; and the stereospecificity [mmmm] ofthe polymer was 95.9%.

INDUSTRIAL APPLICABILITY

The present invention provides solid catalyst components with highactivity and high stereospecificity for olefin polymerization, catalystsfor olefin polymerization and processes for producing olefin polymers,for which are used, as the electron donor, compounds with no problems ofsafety and hygiene. The compounds for the electron donor are inexpensiveand are easy to produce.

What is claimed is:
 1. A solid catalyst component for olefinpolymerization, comprising titanium, magnesium, and a compound of thefollowing general formula (I) as an electron donor:

wherein R¹ and R²may be the same or different and each represents alinear or branched hydrocarbon group having from 1 to 20 carbon atoms;and n is an integer of from 1 to
 10. 2. A catalyst for olefinpolymerization, comprising (A) the solid catalyst component for olefinpolymerization of claim 1, and (B) an organoaluminium compound.
 3. Acatalyst for olefin polymerization, comprising (A) the solid catalystcomponent for olefin polymerization of claim 1, (B) an organoaluminiumcompound, and (C) an electron-donating compound as the third component.4. The catalyst for olefin polymerization as claimed in claim 3, whereinthe electron-donating compound for the third component (C) is anorganosilicon compound.
 5. A process for producing olefin polymers,which comprises polymerizing olefins in the presence of the catalyst forolefin polymerization of claim
 2. 6. A process for producing olefinpolymers, which comprises polymerizing olefins in the presence of thecatalysts for olefin polymerization of claim
 3. 7. A process forproducing olefin polymers, which comprises polymerizing olefins in thepresence of the catalysts for olefin polymerization of claim 4.